1. Technical Field
The present invention relates to a nozzle state detecting apparatus that detects the states of a plurality of nozzles included in an ejecting head ejecting fluids from the nozzles by respectively driving a plurality of piezoelectric elements provided in the ejecting head and equal in number to the nozzles, and an image forming apparatus that ejects a fluid on a medium to form an image thereon.
2. Related Art
There has been proposed a nozzle state detecting apparatus of such a type that determines an ejection failure (dropped dots) of a nozzle by detecting residual vibration of a vibrating plate when an electrostatic actuator is driven in an ink jet printer including an ink jet head which causes the electrostatic actuator to vibrate the vibrating plate to contract the volume of a cavity (ink chamber), thereby ejecting ink droplets from the nozzle communicating with the cavity (see, for example, JP-A-2004-306529). When ink dries and, for example, adheres near a nozzle, causing an ejection failure, the frequency of the residual vibration becomes low as compared with the case of normal ejection. Accordingly, this detecting apparatus detects the period of residual vibration, and compares the detected period of residual vibration with the period of residual vibration in the case of normal ejection to thereby accurately detect an ejection failure of a nozzle.